P o iling key excipien s in comme cial o al
an ibio ic suspensions: a desc ip i e s udy o
o mula ion ends and selec ed sa e y conce ns
Twana Mohammed M. Ways1
1 Depa men o Pha maceu ics, College o Pha macy, Uni e si y o Sulaimani, Sulaymaniyah, 46001, Ku dis an Region, I aq
Co esponding au ho :
Twana Mohammed M. Ways ( wa[email p o ec ed]u.iq)
Recei ed
6 July 2025♦
Accep ed
17 Sep embe 2025♦
Published
9 Oc obe 2025
Ci a ion:
M. Ways TM (2025) P o iling key excipien s in comme cial o al an ibio ic suspensions: a desc ip i e s udy o o mula ion
ends and selec ed sa e y conce ns. Pha macia 72: 1–10. h ps://doi.o g/10.3897/pha macia.72.e164270
Abs ac
The e is limi ed desc ip i e da a on excipien use in o al an ibio ic suspensions; his s udy p o ides a no el e alua ion o commonly
used excipien s and hei o mula ion a ionale. A o al o 41 suspensions ep esen ing nine an ibio ic ypes we e analyzed using
pa ien in o ma ion lea le s. The equency o each excipien class was de e mined, and associa ions be ween suspending agen s o
p ese a i es and an ibio ic classes we e assessed. Selec ed quali a i e sa e y conce ns ela ed o he lis ed excipien s we e iden i ied.
Amoxicillin/cla ulana e was he mos equen ly ep esen ed an ibio ic. Excipien de ails we e a ailable in 31 p oduc s, while 10
lacked disclosu e. Xan han gum, sodium benzoa e, suc ose, i anium dioxide, and s awbe y la o we e he mos commonly used
suspending agen , p ese a i e, swee ene , colo an , and la o ing agen , espec i ely. Combina ions o suspending agen s, pa icu-
la ly xan han gum wi h colloidal silicon dioxide, we e common, whe eas p ese a i e combina ions we e a e. A signi ican associa-
ion was obse ed be ween he ype o suspending agen and he an ibio ic class (p < 0.001), as well as be ween p ese a i e ype and
an ibio ic class (p = 0.001). The indings highligh o mula ion pa e ns, sa e y conce ns, and anspa ency issues, p o iding no el
insigh s o suppo sa e pha maceu ical p oduc s and guide egula o y p ac ice.
Keywo ds
excipien s, pedia ic o mula ions, p ese a i es, sa e y conce ns, suspending agen s, suspensions, swee ene s
In oduc ion
O al suspensions a e commonly used o deli e d ugs ha
a e insoluble o uns able in solu ion. An ibio ics a e o en
o mula ed as o al suspensions because many a e uns able
in aqueous solu ion bu emain s able in d y powde o m
un il econs i u ion. This s a egy ex ends he shel li e and
imp o es he he apeu ic e icacy o he p oduc s. O al
suspensions also play a i al ole in he e ec i e deli e y o
an ibio ics because o hei sui abili y o pedia ic, ge ia -
ic, and o he pa ien s wi h di icul y swallowing able s
and capsules (Fox 2014). Suspensions ha e imp o ed lex-
ibili y in dosing, which allows easy adjus men o doses
by changing he olume adminis e ed (using calib a ed
dosing de ices such as sy inges and spoons). This is pa -
icula ly bene icial o he adminis a ion o an ibio ics in
pedia ic pa ien s o hose equi ing p ecise weigh -based
dosing, including pa ien s wi h enal and hepa ic diseases
(Aul on and Taylo 2022).
A ange o excipien s, including suspending agen s, an-
imic obial p ese a i es, swee ene s, colo an s, and la-
o ing agen s, is equi ed in he o mula ion o sa e, s able,
Copy igh M. Ways TM. This is an open access a icle dis ibu ed unde he e ms o he C ea i e Commons A ibu ion License
(CC-BY 4.0), which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal au ho and sou ce
a e c edi ed.
Pha macia 72: 1–10
DOI 10.3897/pha macia.72.e164270
Resea ch A icle
M. Ways TM: Key excipien s and sa e y conce ns in o al an ibio ic suspensions2
pala able, and e ec i e suspensions (Aul on and Taylo
2022; Gaikwad e al. 2024). Ideally, he excipien s should
no ha e any pha macological ac i i ies o he apeu ic
uses, al hough hey a e used o imp o e physical s abili-
y (no app eciable sedimen a ion), chemical s abili y o e
he equi ed ime (shel li e), iscosi y, o ganolep ic p op-
e ies, and he biopha maceu ical p ope ies o he d ug
p oduc s (Mo e on 2010; Elde e al. 2016). Suspending
agen s a e used o main ain he uni o m dis ibu ion o
d ug pa icles in he liquid medium, usually by enhancing
he iscosi y o he medium, which ensu es consis en dos-
ing. P ese a i es inhibi mic obial g ow h and ensu e he
sa e y and s abili y o suspensions du ing s o age and use
(ex ending he shel li e a e econs i u ion) (Rouaz e al.
2021; Bobillo e al. 2024). Swee ene s and la o ing agen s
p o ide swee ness o he p oduc s, can mask he bi e o
me allic as e o an ibio ics, and make he suspensions
mo e pala able (especially o child en), he eby imp o -
ing pa ien compliance. Colo ing agen s enhance he isu-
al appeal o suspensions, imp o e pa ien accep ance, and
acili a e p oduc iden i ica ion (Aul on and Taylo 2022).
The sa e y p o ile o excipien s used in o al suspensions
mus be conside ed p io o hei use in o mula ions
(Ab an es e al. 2016; Belayneh e al. 2020; Bobillo e al.
2024). Some excipien s a e used a low concen a ions and
a e he e o e unlikely o lead o ad e se e ec s. Howe e ,
o he s can igge a al anaphylac ic o alle gic eac ions
in in ole an indi iduals o child en, e en when used a
low concen a ions (Balbani e al. 2006). The e o e, p ope
in o ma ion abou excipien s, including hei names, unc-
ional ca ego ies, and any ad e se e ec s, mus be clea ly
p o ided by pha maceu ical manu ac u e s. This may help
in he iden i ica ion o p oduc s wi h desi ed physico-
chemical, biopha maceu ical, and he apeu ic p ope ies.
The li e a u e lacks da a on he ype, equency, and
commonali y o speci ic excipien s in o al suspensions o
an ibio ics. To he bes o ou knowledge, no published
s udy has epo ed he equency and commonali y o
suspending agen s in comme cially a ailable o al suspen-
sions. Speci ically, he e is no publicly a ailable esea ch
on he excipien s used in he o mula ion o comme cially
a ailable o al an ibio ic suspensions ma ke ed in Sulay-
maniyah and he Ku dis an Region o I aq. This lack o
da a is compounded by he absence o excipien labeling
egula ions and inconsis en disclosu e p ac ices in he
Ku dis an Region and I aq, which highligh s he need o
such da a. This gap in he li e a u e may ha e signi ican
implica ions o bo h pa ien s and heal hca e p o ession-
als. Addi ionally, he lack o da a on excipien ypes can
hinde quali y con ol es ing (e.g., assay, s abili y), as un-
de s anding excipien composi ion is essen ial o accu-
a e e alua ion and o selec ing app op ia e p oduc s o
speci ic pa ien popula ions. This may also expose pa ien s
o high isks o ad e se e ec s, which migh no be due o
he e ec s o APIs bu o he excipien s.
Iden i ying commonly used excipien s se es as a
benchma k o u u e o mula ions, educes he ime
and cos associa ed wi h de eloping new p oduc s, and
p o ides insigh in o indus y-s anda d choices, helping
d ug manu ac u e s align hei o mula ions wi h p o en
p ac ices, egional egula ions, and consume p e e ences.
Such in o ma ion is also essen ial o pa ien s, pha ma-
cis s, heal hca e p o ide s, and egula o y bodies. Gi en
ha o al suspensions a e p edominan ly p esc ibed o pe-
dia ic pa ien s, and many o he p oduc s include pedia -
ic dosing guidance, excipien selec ion o en e lec s con-
side a ions o pedia ic ole abili y, pala abili y, and sa e y.
The aim o his esea ch was o desc ibe he equency o
suspending agen s, p ese a i es, swee ene s, colo an s,
and la o ing agen s in comme cially a ailable o al an ibi-
o ic suspensions in Sulaymaniyah, I aq. In addi ion o de-
sc ip i e p o iling, he s udy also analyzed he associa ion
be ween he ypes o suspending agen s and p ese a i es
used and he an ibio ic o mula ions and highligh ed se-
lec ed sa e y conce ns ela ed o he mos commonly used
excipien s. While all samples we e collec ed locally om
communi y pha macies in Sulaymaniyah, I aq, he p od-
uc s we e manu ac u ed in a ange o coun ies, includ-
ing I aq, Sy ia, Tu key, Jo dan, Saudi A abia, Egyp , India,
Swi ze land, and I eland. This di e si y e lec s he na u e
o pha maceu ical supply chains in many de eloping ma -
ke s, whe e p oduc s om bo h egional and in e na ion-
al manu ac u e s a e commonly dis ibu ed. As such, he
indings could o e no only an o e iew o he local pha -
maceu ical ma ke bu also indica i e insigh s in o o mu-
la ion ends encoun e ed in simila heal hca e se ings.
Ma e ials and me hods
Selec ion o o mula ions
O al suspensions con aining an ibio ics om di e en
classes we e selec ed. Fo y-one o al suspensions we e
included, co e ing se en b oad an ibio ic classes: pen-
icillins, penicillins/be a-lac amase inhibi o s, cephalo-
spo ins, cephalospo ins/be a-lac amase inhibi o s, mac-
olides, ni oimidazoles, and sul onamides/dihyd o ola e
educ ase inhibi o s. Wi hin hese classes, nine di e en
ypes o APIs we e analyzed. These p oduc s we e com-
me cially a ailable in local pha macies o Sulaymaniyah,
Ku dis an Region, I aq. A con enience sampling app oach
was used, whe eby mos comme cially a ailable o al an-
ibio ic suspensions ound in communi y pha macies in
Sulaymaniyah du ing he da a collec ion pe iod we e in-
cluded. Mul iple b ands and dosage s eng hs o he same
API we e coun ed as dis inc p oduc s o e lec ma ke
di e si y. The selec ed an ibio ic classes ep esen ed he
mos widely a ailable o al suspensions in local pha ma-
cies du ing he da a collec ion pe iod; o he classes, such
as e acyclines, we e no included due o limi ed a ail-
abili y in suspension o m locally. The ci y was selec ed
based on accessibili y and logis ical easibili y. While he
s udy was limi ed o one geog aphical loca ion, he sample
is belie ed o be ep esen a i e o he ange o p oduc s
commonly a ailable in he egion.
Pha macia 72: 1–10 3
Al hough he p oduc s we e no es ic ed o hose ex-
clusi ely ma ke ed as pedia ic o mula ions, o al suspen-
sions a e p edominan ly p esc ibed o child en, and he
majo i y o he included o mula ions p o ided explici
pedia ic dosing ins uc ions in hei package lea le s. This
jus i ied he emphasis on pedia ic sa e y conside a ions
in he analysis and discussion. The p oduc s included in
his s udy we e in ended o o al adminis a ion and we e
a ailable ei he as eady- o-use o al suspensions o as
powde s o econs i u ion. The equency o excipien s—
suspending agen s, p ese a i es, swee ene s, colo an s,
and la o ing agen s—in di e en p oduc s was analyzed
based on he in o ma ion p o ided in he pa ien in o -
ma ion lea le (PIL). Only excipien s explici ly lis ed in he
p oduc lea le s we e included in he analysis; ambiguous
o pa ially disclosed excipien s (e.g., unknown la o ing
agen s) we e ca ego ized acco dingly, and p oduc s lacking
iden i iable excipien da a we e excluded om he ele an
analysis. Only excipien p esence was eco ded; no chem-
ical es ing o quan i a i e analysis was conduc ed. Da a
we e collec ed and analyzed om Augus o Oc obe 2024.
Ca ego iza ion o excipien s o analysis
The unc ion o he excipien s in he suspensions was
de e mined based on he excipien monog aphs om
he “Handbook o Pha maceu ical Excipien s” (Sheskey
e al. 2017). Occasionally, some manu ac u e s p o ided
in o ma ion on he unc ion o he excipien s in he PIL,
and his in o ma ion was also included in he analysis.
All excipien s ha we e used as suspending agen s, p e-
se a i es, swee ene s, colo an s, o la o ing agen s we e
iden i ied, and hei occu ence and equency (%) in he
o mula ions we e calcula ed.
S a is ical analysis
Fishe ’s exac es was used o e alua e he associa ion be-
ween he ypes o suspending agen s o p ese a i es and
he classes o an ibio ics in he o al suspensions. This es
was selec ed because i is he mos eliable and obus me h-
od o ca ego ical da a wi h small sample sizes o spa se
dis ibu ions, ensu ing ha he epo ed associa ions a e
s a is ically alid and in e p e able. A p- alue o < 0.05
was conside ed s a is ically signi ican . All analyses we e
pe o med using IBM SPSS S a is ics, e sion 25.
E hical app o al
This s udy was conduc ed acco ding o he ele an guide-
lines and egula ions and was app o ed by he E hics and
Resea ch Regis a ion Commi ee (No. PH136-24) a he
College o Pha macy, Uni e si y o Sulaimani, Ku dis an
Region, I aq.
Resul s
The APIs o he o mula ions used in his s udy we e
amoxicillin, amoxicillin/cla ulana e, ce ixime, ce dini ,
ce podoxime/cla ulanic acid, azi h omycin, cla i h omy-
cin, me onidazole, and sul ame hoxazole/ ime hop im.
O he 41 o mula ions analyzed, eigh ( hose con aining
me onidazole and sul ame hoxazole/ ime hop im) we e
liquid suspensions, while he o he 33 we e powde s o
econs i u ion (Table 1). Amoxicillin/cla ulana e was
he mos common API among he s udied suspensions,
accoun ing o 24.39% o he o mula ions, whe eas ce -
podoxime/cla ulanic acid was he leas common (2.43%).
A o al o 12 di e en suspending agen s we e iden i ied
among he p oduc s (Table 2), wi h se e al o mula ions
using mo e han one suspending agen . Xan han gum was
he mos commonly used suspending agen , p esen in
64.5% o he o mula ions, ollowed by colloidal silicon
dioxide (54.8%), which was o en used in combina ion
wi h xan han gum (Figs 1, 2). O he suspending agen s
included sodium ca boxyme hylcellulose, hyd oxyp opyl-
cellulose, hyd oxyp opyl me hylcellulose (HPMC), mi-
c oc ys alline cellulose, mal odex in, and Tween 80. Less
equen ly used suspending agen s, including po idone
K-30, Veegum HV, and A icel g ades 501 and 591, we e
each iden i ied in only one o mula ion. Fi e p oduc s
(16.1%) did no con ain any suspending agen s. Addi ion-
ally, 10 ou o he 41 p oduc s did no disclose excipien
in o ma ion in he pa ien in o ma ion lea le . A s a is i-
cally signi ican associa ion was obse ed be ween an ibi-
Table 1. The ac i e pha maceu ical ing edien s (APIs), ype o pha maceu ical p oduc , equency, and pe cen age o o mu-
la ions analyzed.
Class API Pha maceu ical p oduc F equency o o mula ions n (%)
Penicillins Amoxicillin Powde o econs i u ion 6 (14.63)
Penicillins/be a-lac amase inhibi o s Amoxicillin/cla ulana e Powde o econs i u ion 10 (24.39)
Cephalospo ins Ce ixime Powde o econs i u ion 5 (12.19)
Ce dini Powde o econs i u ion 3 (7.31)
Cephalospo ins/be a-lac amase inhibi o s Ce podoxime/cla ulanic acid Powde o econs i u ion 1 (2.43)
Mac olides Azi h omycin Powde o econs i u ion 5 (12.19)
Cla i h omycin Powde o econs i u ion 3 (7.31)
Ni oimidazoles Me onidazole Liquid suspension 4 (9.75)
Sul onamides/dihyd o ola e educ ase Sul ame hoxazole/ ime hop im Liquid suspension 4 (9.75)
To al 41 (100)
No e: F equency alues a e p esen ed as n (%); alues in pa en heses indica e pe cen ages.
M. Ways TM: Key excipien s and sa e y conce ns in o al an ibio ic suspensions4
o ic class and he ype o suspending agen used (Fishe ’s
Exac Tes , p < 0.001). The con ingency able showed ha
ce ain agen s, such as xan han gum, we e mo e common-
ly used in speci ic an ibio ic classes. Full s a is ical ou pu
is p o ided in he Suppl. ma e ial 1: shee 1.
Fou di e en an imic obial p ese a i es we e iden i-
ied (Table 3), including sodium benzoa e (38.7%), me hyl
pa aben (25.8%), p opyl pa aben (19.3%), and po assi-
um so ba e (12.9%). Eigh o mula ions (25.8%) did no
con ain any an imic obial p ese a i e. Mos p oduc s
con ained a single p ese a i e, while a smalle po ion
used combina ions such as me hyl pa aben wi h p opyl
pa aben (Figs 3, 4). Fishe ’s Exac Tes also e ealed a sig-
ni ican associa ion be ween an ibio ic class and p ese a-
i e ype (p = 0.001). Some p ese a i es appea ed o be
p e e en ially selec ed o ce ain an ibio ics, hough he
dis ibu ion was less consis en . Full de ails a e a ailable
in he Suppl. ma e ial 1: shee 2.
Among he o mula ions analyzed, six ypes o swee en-
e s we e iden i ied: suc ose, saccha in sodium, aspa ame,
Table 2. Types o suspending agen s, hei equency, and pe cen -
age in he o mula ions analyzed. Pe cen ages a e calcula ed based
on he numbe o o mula ions ha lis ed he excipien s (N = 31).
Suspending agen s F equency in
o mula ions n (%)
Xan han gum 20 (64.5)
Colloidal silicon dioxide 17 (54.8)
Sodium ca boxyme hylcellulose 5 (16.1)
Hyd oxyp opylcellulose 5 (16.1)
Hyd oxyp opyl me hyl cellulose (hyp omellose,
HPMC)
4 (12.9)
Tween 80 4 (12.9)
Mic oc ys alline cellulose 3 (9.6)
Mal odex in 3 (9.6)
Po idone k-30 1 (3.2)
Veegum HV(magnesium aluminum silica e) 1 (3.2)
A icel 501 1 (3.2)
A icel 591 1 (3.2)
No suspending agen s 5 (16.1)
No e: F equency alues a e p esen ed as n (%); alues in pa en heses
indica e pe cen ages.
Figu e 2. Numbe o o al an ibio ic suspensions con aining suspending agen s used as single agen s o in combina ion.
0
5
10
15
20
25
Single Combinaon
Numbe
Suspending agen
0
1
2
3
4
5
6
F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
F11
F12
F13
F14
F15
F16
F17
F18
F19
F20
F21
F22
F23
F24
F25
F26
F equency
Fo mulaon
Xan han gum CSD SCMCHPC
HPMCTween 80 MCC Mal odex in
Po idone k-30 Veegum HV A icel 591 A icel 501
Figu e 1. F equency o suspending agen s used in he o al an ibio ic suspensions applied ei he indi idually o in combina ion. CSD:
colloidal silicon dioxide, SCMC: sodium ca boxyme hylcellulose, HPC: hyd oxyp opylcellulose, HPMC: hyd oxyp opyl me hylcel-
lulose, MCC: mic oc ys alline cellulose. Each o mula ion is coded as F1 o F26 o ep esen he 26 indi idual p oduc s analyzed.
Pha macia 72: 1–10 5
sodium cyclama e, so bi ol, and monoammonium glycy -
hizina e (Table 3). Suc ose was he mos equen ly used
swee ene , ound in 26 p oduc s (83.8%). One p oduc did
no con ain any swee ene . While 15 p oduc s con ained
only suc ose, o he s included combina ions o wo o mo e
swee ene s. Th ee p oduc s con ained h ee swee ene s,
and only one p oduc con ained ou swee ene s.
Wi h espec o colo an use, only some amoxicillin
and ce dini suspensions and all o he cla i h omycin sus-
pensions con ained colo an s. Six syn he ic colo an s we e
iden i ied: i anium dioxide, Sunse Yellow FCF, e y h o-
sine, Allu a Red AC, Ponceau 4R, and yellow ood-g ade
colo . In o al, 23 o mula ions (74.1%) did no con ain
any colo an s (Table 3).
Finally, 16 di e en la o ing agen s we e ound
among he o mula ions (Table 4). S awbe y was
he mos common (22.5%), ollowed by banana la o .
F ui -based la o s such as aspbe y, o ange, lem-
on, che y, and mixed ui we e equen ly used. In
some p oduc s o amoxicillin, ce dini , cla i h omycin,
Table 3. Types o an imic obial p ese a i es, swee ene s, and colo an s, hei equency, and pe cen age in he o mula ions ana-
lyzed. Pe cen ages a e calcula ed based on he numbe o o mula ions ha lis ed he excipien s (N = 31).
An imic obial
p ese a i es
F equency in
o mula ions n (%)
Swee ene s F equency in
o mula ions n (%)
Colo an s F equency in
o mula ions n (%)
Sodium benzoa e 12 (38.7) Suc ose 26 (83.8) Ti anium dioxide 3 (9.6)
Me hyl pa aben 8 (25.8) Saccha in sodium 12 (38.7) Sunse yellow FCF (FD&C* yellow No. 6) 2 (6.4)
P opyl pa aben 6 (19.3) Aspa ame 3 (9.6) E y h osine (FD&C Red No. 3) 1 (3.2)
Po assium so ba e 4 (12.9) So bi ol 3 (9.6) Allu a ed AC (FD&C Red No. 40) 1 (3.2)
No an imic obial
p ese a i es
8 (25.8) Sodium cyclama e 1 (3.2) Ponceau 4R 1 (3.2)
Monoammonium
glycy hizina e
1 (3.2) Yellow colo ood g ade 1 (3.2)
No swee ene s 1 (3.2) No colo an s 23 (74.1)
No e: F equency alues a e p esen ed as n (%); alues in pa en heses indica e pe cen ages.
*FD&C = Food, D ugs, and Cosme ics; used in he Uni ed S a es o indica e ha a colo an is ce i ied o use in oods, d ugs, and cosme ics by he U.S. FDA.
Figu e 4. Numbe o o al an ibio ic suspensions con aining p ese a i es used as single agen s o in combina ion.
0
2
4
6
8
10
12
14
16
18
Singl
eC
ombinaon
Numbe
P ese a e
Figu e 3. F equency o p ese a i es used in he o al an ibio ic suspensions applied ei he indi idually o in combina ion. Each
o mula ion is coded as F1 o F23 o ep esen he 23 indi idual p oduc s analyzed.
0
0.5
1
1.5
2
2.5
F1 F2 F3 F4 F5 F6 F7 F8 F9 F10F11 F12F13 F14F15 F16F17 F18F19 F20F21 F22F
23
F equency
Fo mulaon
Sodium benzoa e Me hyl pa abenP opyl pa aben Po assium so ba e
M. Ways TM: Key excipien s and sa e y conce ns in o al an ibio ic suspensions6
me onidazole, and sul ame hoxazole/ ime hop im,
la o ing agen s such as ci ic acid anhyd ous and i-
sodium ci a e we e also included o imp o e pala abil-
i y. One me onidazole o mula ion did no con ain
any la o ing agen despi e i s known bi e ness. Fu -
he mo e, 9.6% o he p oduc s con ained unspeci ied
la o ing agen s.
Discussion
This s udy aimed o analyze he ypes and equency o
commonly used excipien s—pa icula ly suspending
agen s, p ese a i es, swee ene s, colo an s, and la-
o ing agen s—in comme cially a ailable o al suspen-
sions o an ibio ics, wi h a ocus on hei o mula ion
a ionale and implica ions o sa e y, pa icula ly in
pedia ics, and p oduc accep abili y. Gi en ha o al
suspensions a e p edominan ly used in pedia ic pa-
ien s, excipien - ela ed sa e y isks we e in e p e ed in
ligh o pedia ic suscep ibili y, pa icula ly o p ese -
a i es, swee ene s, and colo an s. The p edominance
o powde - o - econs i u ion suspensions in his s udy
can be a ibu ed o he ins abili y o many an ibio -
ics in aqueous media. Only me onidazole and sul a-
me hoxazole/ ime hop im we e ma ke ed as liquid
suspensions, as hey a e chemically s able in aqueous
en i onmen s unde app op ia e pH and empe a u e
condi ions (Ma hew e al. 1994; Białk-Bielińska e al.
2012; Donnelly and Ying 2015). In con as , an ibio ics
such as amoxicillin and cephalospo ins deg ade mo e
apidly in wa e (D’Cos a and W igh 2009; Bahmany e
al. 2023), and o mula ing hem as powde s o econ-
s i u ion signi ican ly imp o es hei shel li e.
Incomple e o inconsis en labeling o excipien s e-
mains a signi ican ba ie o e alua ing he sa e y and
quali y o pha maceu ical p oduc s. In ou s udy, 24% o
o al an ibio ic suspensions lacked excipien disclosu e.
This issue was e en mo e p onounced in a s udy conduc -
ed in Nige ia, whe e 51% o pedia ic o al liquid o mu-
la ions did no disclose excipien in o ma ion, e lec ing
a common challenge in pha maceu ical labeling ac oss
di e en egions (So emekun e al. 2019).
Suspending agen s a e essen ial in main aining uni-
o mi y and physical s abili y in o al suspensions. In his
s udy, a di e se ange o suspending agen s was iden-
i ied, o en used in combina ion o op imize heology
and p e en sedimen a ion. Xan han gum was he mos
equen ly used, likely due o i s high iscosi y, he mal
s abili y, and compa ibili y ac oss pH anges (Sheskey
e al. 2017; Layek 2024). Colloidal silicon dioxide, o en
pai ed wi h xan han gum, ac s syne gis ically o enhance
iscosi y and p e en caking. O he agen s such as hy-
d oxyp opylcellulose, HPMC, sodium ca boxyme hyl-
cellulose, and Tween 80 a e well known o hei ela i e
biocompa ibili y, non- oxici y, and abili y o o m s able
suspensions. Less equen ly used suspending agen s,
such as Veegum HV and A icel g ades, may be ese ed
o speci ic o mula ion needs o excluded due o po en-
ial mucosal i i a ion o cos conside a ions. Fo exam-
ple, Veegum HV may cause mucosal o espi a o y i i-
a ion i no p ope ly handled. Veegum HV is ese ed
o o mula ions equi ing high s abili y and iscosi y
in challenging condi ions, such as acidic o high ionic
s eng h en i onmen s, which may no be necessa y in
mos an ibio ic suspensions (López-Galindo and Vise as
2004; López-Galindo e al. 2007; Ali e al. 2010). The
absence o suspending agen s in some p oduc s aises
ques ions ega ding pos - econs i u ion physical s abil-
i y and dosing accu acy, pa icula ly c i ical o pedi-
a ic o mula ions. The signi ican associa ion be ween
suspending agen and an ibio ic class may e lec ex-
cipien compa ibili y wi h speci ic d ug p ope ies. Fo
example, he equen use o xan han gum, ei he alone
o in combina ion, in cephalospo in suspensions may
ela e o i s a o able heological p ope ies and abili y
o main ain physical s abili y in aqueous o mula ions.
Howe e , a ia ions could also s em om manu ac u -
e -speci ic o mula ion s a egies a he han pha ma-
cological equi emen s. O e all, he indings emphasize
he widesp ead use o polyme ic suspending agen s and
he equen eliance on combina ions o achie e desi -
able suspension cha ac e is ics. An imic obial p ese -
a i es play a c i ical ole in p e en ing con amina ion
du ing use, pa icula ly in mul i-dose p oduc s. Sodi-
um benzoa e was he mos common p ese a i e, due
o i s cos -e ec i eness, accep able sa e y p o ile, and
b oad-spec um ac i i y. Pa abens (me hyl and p opyl)
we e also commonly used, o en in combina ion o en-
hance an imic obial e icacy. These pa abens a e es e s
o p-hyd oxybenzoic acid and a e widely employed in
Table 4. Types o la o ing agen s, hei equency, and pe cen -
age in he o mula ions analyzed. Pe cen ages a e calcula ed based
on he numbe o o mula ions ha lis ed he excipien s (N = 31).
Fla o ing agen s F equency in o mula ions n (%)
S awbe y la o 7 (22.5)
Banana la o 6 (19.3)
Ci ic acid anhyd ous 5 (16.1)
Raspbe y la o 5 (16.1)
Mix ui la o 5 (16.1)
O ange la o 4 (12.9)
Unknown la o ing agen 3 (9.6)
Lemon la o 2 (6.4)
Vanilla la o 2 (6.4)
Vanillin 1 (3.2)
T isodium ci a e 1 (3.2)
C eam ca amel 1 (3.2)
Ci ic acid monohyd a e 1 (3.2)
C eam la o s 1 (3.2)
Che y la o 1 (3.2)
Tange ine liquid la o 1 (3.2)
No la o ing agen s 1 (3.2)
No e: F equency alues a e p esen ed as n (%); alues in pa en heses
indica e pe cen ages.
Pha macia 72: 1–10 7
pha maceu ical, ood, and cosme ic p oduc s o p ese -
a ion. Ou indings align wi h a Nige ian s udy, which
also epo ed me hylpa aben, p opylpa aben, and sodi-
um benzoa e as common p ese a i es in pedia ic o al
liquids (So emekun e al. 2019). Se e al excipien s iden-
i ied in ou s udy, such as sodium benzoa e and pa -
abens, a e associa ed wi h ad e se e ec s o egula o y
sa e y limi s in pedia ic popula ions. Sodium benzoa e,
o example, poses a pa icula isk in neona es due o
i s abili y o displace bili ubin om albumin, po en ially
leading o hype bili ubinemia and ke nic e us, especially
in hose wi h imma u e me abolic pa hways. Addi ional-
ly, limi ed capaci y o me abolize benzoic acid in in an s
unde 8 weeks aises conce ns abou i s accumula ion
and oxici y, which necessi a es cau ion e en a le els
wi hin he accep ed daily in ake (Eu opean Medicines
Agency 2017). Pa abens, including me hylpa aben and
p opylpa aben, while widely used, ha e de ined accep -
able daily in akes due o conce ns abou hei po en ial
biological e ec s, including endoc ine dis up ion such
as in e e ence wi h es ogen and es os e one egula ion
obse ed in animal s udies. Al hough such e ec s ha e
no been con i med in humans, hey a e o pa icula
conce n in pedia ic popula ions, whe e he endoc ine
sys em is s ill de eloping and may be mo e ulne able
o dis up ion (Eu opean Medicines Agency 2015). These
indings aise po en ial sa e y conce ns and unde sco e
he impo ance o excipien choice and labeling o pha -
maceu ical p oduc s dis ibu ed in Sulaymaniyah and
ac oss he b oade Ku dis an Region.
The p edominance o single-agen p ese a i e use
sugges s a o mula ion p e e ence o simple an imic o-
bial s a egies, likely o educe po en ial d ug–excipien
in e ac ions o egula o y complexi y. Howe e , com-
bina ions o p ese a i es may be employed o b oaden
an imic obial co e age o enhance p ese a i e e icacy
h ough syne gis ic e ec s. In line wi h ou indings, Bal-
bani e al. (2006) ound ha me hylpa aben was he mos
common an imic obial p ese a i e in o al p epa a ions
(45.2%), and sodium benzoa e was p esen in 32.8% o he
p epa a ions. The e a e con o e sies ega ding he use
o pa abens; howe e , many s udies ha e demons a ed
ha pa abens a e non- e a ogenic, non-mu agenic, and
non-ca cinogenic, and ha eal e idence o hei oxic-
i y in humans has no been es ablished (Ma e al. 2016;
Pe ic e al. 2021). Po assium so ba e, hough e ec i e,
was less equen ly used. The absence o p ese a i es in
a la ge numbe o he o mula ions aises sa e y conce ns,
especially in he absence o an imic obial e icacy es -
ing. While he associa ion be ween p ese a i e ype and
an ibio ic class was s a is ically signi ican (p = 0.001), i
should be in e p e ed cau iously due o he small sample
size. Fac o s such as p oduc pH, suga con en , and eg-
ula o y p e e ences likely in luence p ese a i e selec ion
mo e han he an ibio ic i sel . The obse ed pa e ns may
e lec o mula ion adi ions a he han mic obiological
necessi y. Howe e , u u e s udies wi h la ge da ase s and
s a i ied analyses a e needed o explo e po en ial asso-
cia ions be ween excipien selec ion and an ibio ic class
while accoun ing o con ounding ac o s such as manu-
ac u e -speci ic o mula ion p ac ices.
Swee ene s we e p esen in nea ly all o mula ions, wi h
suc ose domina ing due o i s dual ole in enhancing as e
and inc easing iscosi y, which aids in he s abili y o sus-
pensions. While suc ose enhances bo h as e and iscosi y,
i s high con en in pedia ic o mula ions may con ibu e
o den al ca ies and unheal hy suga exposu e, and i s use
is discou aged by he Ame ican Hea Associa ion (Vos
e al. 2017). The inclusion o mul iple swee ene s in some
o mula ions e lec s e o s o mask unpleasan as es,
pa icula ly o pedia ic compliance (Walsh e al. 2014).
The iden i ica ion o swee ene s no lis ed in he FDA In-
ac i e Ing edien s Da abase, such as sodium cyclama e and
monoammonium glycy hizina e (FDA 2024), wa an s
u he e alua ion ega ding hei sa e y and egula o y
accep ance. Sodium cyclama e is banned in he Uni ed
S a es due o ea lie sa e y conce ns bu emains pe mi ed
in some coun ies unde speci ic in ake limi s. I s inclusion
in pedia ic medicines may e lec egional egula o y al-
lowances o cos conside a ions. Howe e , gi en he limi -
ed pedia ic sa e y da a o such addi i es, hei use should
ollow in e na ional pha maceu ical guidelines, such as
hose issued by he EMA, WHO, and FDA.
Colo an s we e limi ed o a small numbe o o mu-
la ions, ypically hose wi h amoxicillin, ce dini , o
cla i h omycin. All iden i ied colo an s we e syn he ic.
Mos , including i anium dioxide, Sunse Yellow FCF,
e y h osine, and Allu a Red AC, a e app o ed by he
U.S. FDA o use in oods, d ugs, and cosme ics. (FDA
2022). Ponceau 4R is no app o ed o use in he Uni ed
S a es, al hough i is pe mi ed in o he egions such
as he Eu opean Union. One colo an , labeled only as
“yellow ood-g ade colo ,” could no be clea ly iden-
i ied and may no co espond o a speci ic FDA-ap-
p o ed colo an . Al hough FDA-app o ed colo an s
a e gene ally ega ded as sa e, he e a e some conce ns
abou hei impac on human heal h, and he sea ch o
al e na i es— o example, na u al colo an s—is also
encou aged (Pé ez-Iba bia e al. 2016; Hancock e al.
2024). Howe e , he issue o poo s abili y o na u al
colo an s could p e en hei use in pha maceu ical
o mula ions. Ti anium dioxide was he mos common-
ly used colo an , likely due o i s aes he ic appeal, opac-
i y, high chemical s abili y, biocompa ibili y, and low
oxici y (Fei Yin e al. 2013). Howe e , ecen conce ns
ega ding i s po en ial geno oxici y, pa icula ly in he
EU, ha e p omp ed calls o limi i s use (Abend e al.
2024). The majo i y o he p oduc s we e colo an - ee,
which aligns wi h Eu opean egula o y ecommenda-
ions ha ad ise minimizing excipien s o known ad-
e se e ec , including syn he ic dyes, especially in pe-
dia ic o mula ions whe e some colo an s ha e been
associa ed wi h beha io al e ec s such as hype ac i i y
(Eu opean Medicines Agency 2006).
M. Ways TM: Key excipien s and sa e y conce ns in o al an ibio ic suspensions8
Fla o ing agen s we e a ied and domina ed by ui
la o s, which aligns wi h pedia ic p e e ences, as
child en p e e ui la o s o e adi ional la o ing
agen s such as men hol and capsicum (Eccles 2020).
S awbe y and banana we e he mos common. Ad-
di ional excipien s such as ci ic acid and isodium
ci a e we e used o mask he as e o bi e APIs. The
absence o a la o ing agen in one me onidazole p od-
uc is no able, conside ing he known bi e ness o his
API (Gadalla e al. 1984). The p esence o unspeci ied
la o ing agen s in se e al p oduc s may aise sa e y
conce ns o sensi i e popula ions and e lec s a lack o
anspa ency in excipien disclosu e. This emphasizes
he need o s ic e egula o y s anda ds equi ing he
ull lis ing o all excipien s, including la o ing agen s,
o enhance pa ien sa e y and in o med clinical deci-
sion-making. Fla o ing agen s may include alle gens o
complex mix u es ha a e no adequa ely e alua ed in
child en. Clea disclosu e is essen ial o a oid unin en-
ional exposu e and o align wi h egula o y s anda ds.
The indings o he cu en s udy highligh inconsis en-
cies in excipien selec ion and labeling in o al an ibio ic
suspensions and poin o he need o imp o ed adhe -
ence o egula o y guidelines, pa icula ly ega ding
sa e y disclosu e, a oidance o excipien s wi h known
isk, and o mula ion anspa ency.
In ligh o hese indings, i is impo an o consid-
e how cu en egula o y amewo ks guide he se-
lec ion and disclosu e o excipien s in pha maceu ical
p oduc s. The Eu opean Medicines Agency has ou -
lined excipien - ela ed sa e y conce ns, u ging manu-
ac u e s o e alua e isks on a case-by-case basis and
o a oid po en ially ha m ul excipien s when possible
(Eu opean Medicines Agency 2006). Fu he mo e, he
Eu opean Commission’s guideline on excipien label-
ing manda es he disclosu e o excipien s known o
ha e a ecognized ac ion o e ec in all pa ien s, wi h
special a en ion o hei impac on ulne able g oups
such as pedia ic popula ions (Eu opean Commission
2003). Despi e hese egula o y e o s, implemen a ion
emains inconsis en , pa icula ly in low- egula ion
coun ies, including I aq, whe e impo ed and locally
manu ac u ed p oduc s may no uni o mly ollow such
s anda ds. The U.S. Food and D ug Adminis a ion’s In-
ac i e Ing edien Da abase (FDA 2024) also se es as
a use ul benchma k o excipien accep abili y, hough
pedia ic-speci ic exposu e da a emain limi ed. These
egula o y documen s p o ide impo an guidance o
ensu ing o mula ion sa e y, and ou indings unde -
sco e he gap be ween such s anda ds and eal-wo ld
excipien use in o al an ibio ic suspensions in Sulay-
maniyah and he b oade Ku dis an Region.
Al hough he s udy is geog aphically limi ed, he in-
clusion o p oduc s om mul iple in e na ional manu-
ac u e s enhances he ele ance o he indings o o he
ma ke s wi h compa able pha maceu ical sou cing and
egula o y con ex s. A limi a ion o his s udy is he eli-
ance on lea le -disclosed excipien lis s, which may no
always e lec he ull composi ion o he o mula ions.
Addi ionally, he in o ma ion in PILs may no always be
upda ed o e lec he mos ecen o mula ion changes.
Mo eo e , undecla ed excipien s, especially hose used
as suspending agen s, p ese a i es, o colo an s, may
a ec sa e y in e p e a ions. Howe e , in his s udy, he
inclusion c i e ia ensu ed ha only p oduc s wi h ade-
qua e excipien disclosu e we e analyzed. The sa e y- e-
la ed discussion in his s udy is quali a i e in na u e.
As excipien concen a ions we e no p o ided in mos
PILs, no quan i a i e sa e y assessmen s could be made.
Addi ionally, unc ional classi ica ion o excipien s was
p ima ily based on ypical excipien oles epo ed in
he li e a u e and s anda d e e ences, a he han on
expe imen al e i ica ion o manu ac u e -speci ied
unc ions, which could in oduce unce ain y ega d-
ing he ac ual unc ion o each excipien in he inal
p oduc . We acknowledge ha hese me hodological
cons ain s limi he dep h o in e p e abili y o he
indings. None heless, despi e he eliance on PIL da a
and he ela i ely small sample size, he s udy p o ides
a sys ema ic and egionally ep esen a i e e alua ion o
excipien usage pa e ns in o al an ibio ic suspensions,
o e ing insigh s ha a e bo h me hodologically obus
wi hin hese limi a ions and p ac ically ele an .
Conclusion
This s udy p o ides essen ial new in o ma ion on he
ypes, equency, and combina ion pa e ns o excipien s
used in he o mula ion o o al suspensions o an ibio -
ics. Xan han gum, sodium benzoa e, suc ose, i anium
dioxide, and s awbe y la o we e he mos common
excipien s iden i ied. No ably, many p oduc s used com-
bina ions o suspending agen s o p ese a i es, wi h
xan han gum and colloidal silicon dioxide being he mos
equen ly co-used suspending agen s. In con as , single
p ese a i es we e mo e commonly used han combina-
ions. Ou indings o e aluable insigh s o clinicians,
pha macis s, and o mula o s when conside ing he
sa e y, e icacy, and accep abili y o o al suspensions o
an ibio ics. Fu he mo e, iden i ying ends in excipien
combina ions (e.g., xan han gum wi h colloidal silicon
dioxide as suspending agen s) can guide a ional o mu-
la ion de elopmen , which is especially impo an o
pedia ic popula ions whe e p oduc s abili y, sa e y, and
pala abili y a e c i ical. Al hough his s udy ocused on
suspensions a ailable in Sulaymaniyah, u u e esea ch
compa ing excipien use ac oss di e en egions and
p oduc ypes may e eal b oade ends and enhance
o mula ion s a egies. Addi ionally, he indings unde -
sco e he need o comple e and consis en disclosu e
o excipien con en in he pa ien in o ma ion lea le ,
which is essen ial o egula o y anspa ency, in o med
clinical decisions, and imp o ed public heal h—pa ic-
ula ly o child en, as o al suspensions a e commonly
used in pedia ic ca e.
Pha macia 72: 1–10 9
Acknowledgmen s
The au ho hanks he Uni e si y o Sulaimani o hei
suppo in conduc ing his s udy.
Addi ional in o ma ion
Con lic o in e es
The au ho has decla ed ha no compe ing in e es s exis .
E hical s a emen s
The au ho s decla ed ha no clinical ials we e used in he p es-
en s udy.
The au ho s decla ed ha no expe imen s on humans o hu-
man issues we e pe o med o he p esen s udy.
The au ho s decla ed ha no in o med consen was ob ained
om he humans, dono s o dono s’ ep esen a i es pa icipa -
ing in he s udy.
The au ho s decla ed ha no expe imen s on animals we e
pe o med o he p esen s udy.
The au ho s decla ed ha no comme cially a ailable im-
mo alized human and animal cell lines we e used in he
p esen s udy.
Use o AI
No use o AI was epo ed.
Funding
No unding was epo ed.
Au ho con ibu ions
Concep ualiza ion, me hodology, in es iga ion, esou ces, w i -
ing—o iginal d a , w i ing— e iew and edi ing: TMM.
Au ho ORCIDs
Twana Mohammed M. Ways h ps://o cid.o g/0000-0002-
7595-2159
Da a a ailabili y
All o he da a ha suppo he indings o his s udy a e a ailable
in he main ex o Supplemen a y In o ma ion.
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